Mine roof supports



y 1968 A. ORMEROD 3,383,867

MINE ROOF SUPPORTS Filed Dec. 27, 1965 2 Shets-Sheet 1 INVENTOR:

ALAN ORMERoD Q BY. I 2

Attqs.

May 21, 1968 Filed Dec. 27, 1965 A. ORMEROD 3,383,867

MINE ROOF SUPPORTS 2 Sheets-Shee 2 INVENTOR;

A AN ORNEROD United States Patent Office Patented May 21, 1968 3,383,867MINE RGGF SUPPORTS Alan Ormerod, Charley, England, assignor to GullickLimited, Wigan, Lancashire, England, a British company Filed Dec. 27,1965, Ser. No. 516,385 Claims priority, application Great Britain, Jan.15, 1965, 1,789/ 65 6 Claims. (Cl. 61-45) ABSTRACT OF THE DISCLOSURE Thetwo support units of a self-advancing mine roof support are connected bya resilient tie bar. The tie bar is pivotally connected to one unit andto the other unit by mechanism which stresses the bar to oppose tiltingmotion of such other unit thereby to maintain it in required angulardisposition in a plane normal to the mineral face.

This invention is for improvements in or relating to self-advancing orpowered mine roof supports.

The invention is particularly, although not exclusively, concerned withimprovements in or modifications of roof supports which comprise atleast two roof-supporting units arranged in tandem or one behind theother, the two units being articulated or pivotally linked together attheir lower parts. A pressure-fluid ram device is incorporated in thesupport for advancing it. In some constructions this ram also serves topush over a conveyor towards the mineral face as cutting of the mineralproceeds. The ram device generally uses the conveyor as an anchorage orabutment for advancing the support.

In one known arrangement one roof support unit has a plurality of legsor props and the other unit has a single leg or prop. A roof-engagingstructure of the support has a part supported on and between the upperparts of said plurality of legs or props and a cantilever part supportedby an upper part of the single leg or prop. The two units arearticulated together at their lower parts by rigid tie-bar meanspivotally connected to each unit. This arrangement permits one unit toadjust itself vertically with respect to the other so that it can moreeasily ride over a rough or uneven floor.

In certain circumstances, for instance with certain types of roof andfloor conditions, especially in high seam workings, it is desirable,when advancing the roof support, to exercise a limited amount of controlor restriction on the angular movement or disposition of one unit orelement relatively to the other. For instance, in high seam workings,where the height of the front unit relatively to its base length isconsiderable, there is a natural tendency for said unit to tilt uponmeeting a step in the floor, which step may have been created by thecoal cutting machine.

Brief summary of the invention The invention is for a self-advancingmine roof support comprising two support units arranged one behind theother and having separate bases connected together by tie-bar means, theconnection between at least one of said bases and said tie-bar meansbeing a pivotal conbar means arranged so that it will act on said unit,

during the rase and fall thereof, to maintain a required angulardisposition of the unit in a plane normal to the mineral face.Preferably means is provided both above and below the tie-bar means andspaced from the pivotal connection thereof to the base of one of theunits whereby the resilient tie-bar means can be caused to restraintilting of said unit about said pivotal connection either towards oraway from the mineral face or both towards and away from the mineralface. Said tilt controlling means may comprise a pin or pins adapted tobe inserted in one or both of two holes in the base of the forward unitand positioned one above and one below the tie-bar means and adjacentthereto.

According to the present invention there is provided a mine roof supportcomprising two supporting units arranged one behind the other or intandem and connected together at their lower parts by a resilienttie-bar, said tie-bar being pivotally connected to at least one of thesupport units so that one unit can rise or fall with respect to theother, the resiliency of the tie-bar acting or serving during the riseand fall of said unit to maintain a required angular disposition of theunit in a plane normal to the mineral face.

The expression resilient tie-bar Where used in this specification inintended to include not onlv a tie-bar which is inherently resilientbecause of the material of which it is made but also a tie-bar whichderives its resiliency from being resiliently mounted.

Preferably there are two or more of said tie-bars in parallelrelationship.

One particular embodiment of the invention will now be described, by wayof example, with reference to the accompanying drawings in which:

FIGURE 1 is a side elevation of the support,

FIGURE 2 is a plan view of the support with part of the roof-barstructure broken away to show the tie-bar arrangement more clearly,

FIGURE 3 is a fragmentary side elevation showing the support negotiatinga step in the floor,

FIGURES 4, 5 and 6 are diagrammatic views showing alternativearrangements for applying control to the forward unit or element of thesupport through the tie-bar arrangement which links the two elements orunits of the support together at their lower parts, and

FIGURE 7 shows a modification.

Referring to the drawings, the support comprises a rear unit. 10 and aforward unit 11.

The rear unit 10 has a base structure 12 in which are pivotally mountedfour hydraulicallyextensible telescopic props 13. These props arearranged in pairs side-byside and pivotally support, at their upperparts, a roof-bar structure or canopy 14.

The forward unit has a base 15 in which there is mounted pivotally, formovement towards and away from the mineral face, a singlehydraulically-extensible telescopic prop or leg 16. This leg pivotallysupports at its upper part, in the usual way, a cantilever roof-barmember 17 pivotally connected at 18 to the roof-bar structure 14.

Pivotally mounted, by means of laterally projecting trunnions 12a in thebase structure 12 of the rear unit or element 10, in a double-actinghydraulic ram 19, the piston of which is pivotally connected to anextension member or relay bar 19a which passes freely through the basestructure 15 of the forward unit or element and is attached, by means ofa clevis 20, to a spill-plate or bracket 21 on the side of the conveyorC which extends along the coal face.

The rear unit it) and the forward unit 11 are articu lated together attheir lower parts by a pair of links or tie-bars 22 pivotally attachedat 23 to the rear unit and pivotally attached at 24 to the forward unit.

The purpose of the doubleacting hydraulic ram 19 is to push over thecoal conveyor C, towards the coal face, as cutting of the coal proceedsafter which the doubleacting ram is retracted and, using the conveyor asan anchorage, drags the support forwardly and up the conveyor.

For the purpose of the present invention the tie-bars or links 22 are ofspring steel and the base structure 15 of the forward unit is providedwith holes to receive transverse pins or bolts 25 and 26 one locatedabove and one located below the tie-bars. It will be noted that the pinsor bolts 25 and 26 are spaced along the tie-bars 22 a short distancefrom the pivots 24.

If (see FIGURES 3 and 4) both control pins 25 and 26 are in position intheir respective holes in the base 15 and the front unit risesrelatively to the rear unit, as shown in FIGURE 3, then the resilienttie bars will take the form shown and will offer a control on the frontunit due to the resilience of the tie-bars. It will be appreciated thata similar restraint will be applied if the front unit is lower than therear unit.

In the instance illustrated in FIGURE the upper pin 25 has been removedand restraint then takes place only in the case of an upward positioningof the forward base relatively to the rear base.

In the instance shown in FIGURE 6 the lower pin 26 has been removed andrestraint then takes place only in the case of a downward positioning ofthe forward base relatively to the rear base.

It follows also that where the front unit has a tendency to tiltforwardly the lower pin or bolt 26 will act to restrain this movementand where the front unit leans backwardly, due for example to steps inthe roof, the upper pin 25 will take control and provide the requiredresilient restraint.

Variations in the positions of the pins 25 and 26 in relation to thepivot 24 will alter the control conditions. Furthermore, spacing of bothpins a greater distance apart will give a limited amount of freemovement before any control is exercised whilst moving one pin only withre spect to the other will result in a limited amount of freedom in onedirection only. A series of alternative holes for the pins 25 and 26may, therefore, be provided.

To exercise even greater control over permissible movement between thetwo units or elements the three-pin arrangement 24, 25 and 26 may berepeated at the connection between the tie-bars and the rear unit orelement using the pivot pin 23 as the third of the three-pin ar--rangement.

FIGURE 7 shows an arrangement in which the tiebars 22 are rigidly boltedto the base of the forward unit as indicated at 27.

Instead of actually making the tie-bars of a resilient material, such asspring steel, a relatively rigid tie-bar, or bars, may be used, such baror bars being resiliently mounted, e.g., by compression springs aboveand below the bar or bars.

In considering the advantages of the invention it should be appreciatedthat there is provided flexibility of movement, as is usual, between theprop 16 and its socketlike base 15. For instance, there may be a rubberbush in the upper part of the base through which the prop passes. Thisflexibility is necessary to allow for roof convergence which moves theroof engaging structure 14, i7, 18 rearwardly in relation to the basestructure 12, 15,

22. Whilst this flexibility of movement is essential when the support isset it is detrimental during advance of the support. For instance, thebase 15 may meet a step in the floor and, but for the arrangementaccording to the invention, would rake up an attitude as shown by theline X-X, The prop 16 will then take up an attitude as shown by the lineY-Y and damage will result at the junction Z between the prop 15 and theupper part of its base 15. By the introduction of the pins 25 and 26 andwith the structure 15, 22 forming a fixed angle of control is offered tothe unit 11, by limiting the angle of tilt, if a step is encounteredduring the advance. During setting of the support between floor and roofa bending force may be applied to the tie members 22 as shown in FIG-URES 3 and 7. By making these members resilient they are capable ofwithstanding this force without permanent deformation.

I claim:

1. A mine roof support comprising, in combination, a first support unitand a second support unit arranged in front of said first unit andspaced therefrom,

said. first unit comprising a base and at least one extensible propmounted on said base,

said second unit comprising a base and at least one extensible propmounted on said base,

a roof-engaging structure carried by the props of said first and secondunits,

means for advancing said units,

a tie-bar joining said bases and being pivotally connected to at leastone of said bases easily to allow the bases of said units to rise andfall with respect to each other as the units are advanced by said means,said tie-bar being a flexible and resilient tie-bar which is stressed bythe rise and fall of one unit with respect to the other when said oneunit encounters and negotiates an obstruction.

and means for transmitting a force from the tie-bar, due to saidstressing thereof, to said one unit during the rise and fall thereofthereby to maintain a required angular disposition of said one unit in aplane normal to the mineral face.

2. A mine roof support according to claim 1 comprising pivot limitingmeans co-operative with the base to which the tie-bar is pivotallyconnected for limiting pivotal movement of said tie-bar relative to saidbase.

3. A mine roof support according to claim 2 wherein said extensible propof the second unit is movably mounted on its base for movement, saidtie-bar being pivotally connected to both bases, and said pivot limitingmeans being between said tie-bar and the base of said second unit.

4. A mine roof support as claimed in claim 2 wherein said pivot-limitingmeans comprises pin means inserted in one or both of two holes in thebase of said unit, said holes being positioned one above and one belowthe tiebar and adjacent thereto.

5. A mine roof support as claimed in claim 1 wherein a roof-bar ispivotally carried by the upper end of the prop of the first unit and aroof-bar is pivotally carried by the upper end of a prop of the secondunit and adjacent ends of said roof-bars are extended to each other andhave means pivotally interconnecting said adjacent ends.

6. A mine roof support comprising, in combination,

a roof supporting structure,

a first support unit and a second support unit arranged in front of thefirst unit and spaced therefrom,

each unit including a base and an extensible prop on the base engagingsaid roof supporting structure whereby said units are independentlymovable in a vertical plane to accommodate for floor irregularities,

mechanism for advancing said units,

and means for constraining said second unit to remain in a requiredangular disposition in a plane normal to References Cited the mineralface while allowing the units easily to FOREIGN PATENTS moveindependently as aforesaid in accommodating for floor irregularities,said means comprising a resil- 831,275 3/ 1960 G t Brit in, ient tie-barpivotally connected to the base of said 5 845,302 8/1950: Great Britain,first unit and extending therefrom to the other base, 358,633 1/1961 Grat Britai and means connecting said tie-bar to said other base 1,375,6399/ 1964 France.

for stressing said t1e-bar in opposition to tipping mo- D AVID I.WILLIAMOWSKY, Primary Examiner' tion of said second unit whereby tomaintain said second unit in said required angular disposition. 10DENNIS TAYLOR, Examiner-

